Aromatics recovery with carbon monoxide-cuprous fluoroborate and carbon monoxide-cuprous fluorophosphate complexes

ABSTRACT

A PROCESS FOR THE SEPARATION OF AROMATIC HYDROCARBONS FROM ADMIXTURE WITH ALIPHATIC HYDROCARBONS OR VINYLAROMATIC HYDROCARBONS WHEREIN SEPARATION IS EFFECTED BY SELECTIVE COMPLEX FORMATION WITH A COMPLEX COMPRISING CUPROUS FLUOROBORATE OR CUPROUS FLUOROPHOSPHATE AND CARBON MONOXIDE.

United States Patent 3,578,581 AROMATICS RECOVERY WITH CARBON MONOXIDE-CUPROUS FLUOROBORATE AND CARBON MONOXIDE-CUPROUS FLUOROPHOSPHATE COMPLEXES George F. Davis, Creve Coeur, Herbert J. Gebhart, Jr., Ferguson, and Earle C. Makin, In, St. Louis, Mo., assignors to Monsanto Company, St. LOUIS, M0. N Drawing. Filed Feb. 12, 1969, Ser. No. 798,778 Int. Cl. BGld 17/00; C07c 7/16 U.S. Cl. 208-308 Claims ABSTRACT OF THE DISCLOSURE A process for the separation of aromatic hydrocarbons from admixture with aliphatic hydrocarbons or vinylaromatic hydrocarbons wherein separation is eifected by selective complex formation with a complex comprising cuprous fluoroborate or cuprous fiuorophosphate and carbon monoxide.

BACKGROUND OF THE INVENTION The present invention relates to a process for the separation, purification and recovery of certain hydrocarbons. More particularly, the present invention is concerned with a process for the separation of aromatic hydrocarbons from admixture with nonaromatic hydrocarbons or vinyl aromatic hydrocarbons utilizing particular complexes of copper fluoroborate and copper fiuorophosphate.

Processes for the separation of aromatic hydrocarbons from saturated aliphatic hydrocarbons, unsaturated aliphatic hydrocarbons or vinyl aromatic hydrocarbons have been proposed wherein the separation is effected by means of copper fluoroborates or copper fluorophosphates. In such processes, it generally is necessary to use the copper salt in the form of its complex with an aromatic and/or olefin hydrocarbon in order to effect the separation. For example, cuprous fluoroborate is readily formed in toluene thereby forming a cuprous fluoroborate-toluene complex which is then contacted with the aromatic hydrocarbon containing mixture to be separated. While this method is quite useful in the separation of aromatic hydrocarbons from nonaromatic hydrocarbons and vinyl aromatic hydrocarbons, at least one problem is presented thereby. This problem is readily illustrated by considering the use of a cuprous fiuoroboratetoluene complex to separate a mixture of close boiling C aromatic and vinylaromatic hydrocarbons. In this illustration, a portion of the hydrocarbons of the mixture to be separated would enter the complex thereby displacing a portion of the toluene from the complex. This displaced toluene would then enter the rafiinate phase thereby adding a component to that phase which would have to be removed by distillation or other means. In addition, the extract phase would contain some toluene and some of the hydrocarbons of the mixture to be separated thereby presenting another phase which also would have to be separated by distillation or other means. While the secondary separation of such extract and millnate phases generally is not particularly difiicult, still it would represent a significant improvement if such secondary separation step could be substantially alleviated or simplified.

It is now an object of the present invention to present a new and improved process for the separation of hydrocarbons by means of complex formation involving cuprous fluoroborate and cuprous fiuorophosphate. It is another object of the present invention to provide a new and improved process for the separation of aromatic hydrocarbons from nonaromatic hydrocarbons and vinylaromatic hydrocarbons from aromatic hydrocarbons whereby both high selectivity and loading capacity are achieved. A remaining object of the present invention is to provide a new and improved process for the separation of aromatic hydrocarbons from nonaromatic hydrocarbons and vinyl aromatic hydrocarbons from aromatic hydrocarbons employing cuprous fluoroborate or cuprous fiuorophosphate wherein the hydrocarbons selectively complexing with such cuprous fluoroborate or cuprous fiuorophosphate are readily recovered therefrom. Yet another object of the present invention is to provide a new and improved process for the separation of hydrocarbons by complex formation with cuprous fluoroborate or cuprous fiuorophosphate wherein the separations and/or recovery steps do not result in the formation of new mixtures requiring additional complicated separation steps. Additional objects will become apparent from the following description of the invention herein disclosed.

SUMMARY OF THE INVENTION The present invention, which fulfills these and other objects, is a process whereby aromatic hydrocarbons may be separated from non-aromatic hydrocarbons and aromatic hydrocarbons may be separated from vinylaromatic hydrocarbons, said process comprising contacting such aromatic hydrocarbon containing mixtures with a complex containing cuprous fluoroborate and/or cuprous fiuorophosphate in complex relationship with carbon monoxide, thereby forming an extract phase and a raflinate phase, separating said extract and raffinate phases and recovering from said extract phase those hydrocarbons of said mixture contained therein.

By means of the process of the present invention, aromatic hydrocarbons may be elfectively separated from saturated or unsaturated aliphatic hydrocarbons. Further, aromatic hydrocarbons may be effectively separated from vinylaromatic hydrocarbons. For the purposes of the present description, vinylaromatic hydrocarbons are those aromatic hydrocarbons having at least one substituent thereto having ethylenic unsaturation, i.e., styrene, alphamethylstyrene, vinyltoluene, and the like. It is a further advantage that in the separation of these hydrocarbon mixtures, the carbon monoxide displaced rapidly evolves from the system thereby substantially reducing or alleviating problems resulting from the formation of new hydrocarbon mixtures which are themselves inconvenient to separate.

DESCRIPTION OF THE PREFERRED EMBODI- MENTS OF THE PRESENT INVENTION In the process of the present invention, separation of the hydrocarbon mixtures is obtained by the selective complexing of aromatic hydrocarbons, in the case of aromatic hydrocarbon-saturated aliphatic hydrocarbon mixtures, unsaturated aliphatic hydrocarbons in the case of aromatic hydrocarbon-unsaturated aliphatic hydrocarbon mixtures, or vinylaromatic hydrocarbons, in the case of vinylaromatic hydrocarbon-aromatic hydrocarbon mixtures. The selective complexing agent utilized in the present process is itself a complex comprised of a cuprous salt and carbon monoxide. The cuprous salts are cuprous tetrafiuoroborate and cuprous hexafluorophosphate which are generally referred to merely as cuprous fluoroborate and cuprous fiuorophosphate. Both of these salts are relatively unstable and cannot be readily formed as the salt. As a result, it is generally necessary to form the salt in the presence of an agent or compound with which the cuprous salt will complex, thereby forming the salt and the complex of the salt with the compound substantially concurrently. The complex of the cuprous salt and carbon monoxide also cannot readily be formed directly and generally, it is necessary to prepare the cuprous saltcarbon monoxide complex by first forming a cuprous salt complex with an organic compound and then replacing at least a portion of the organic compound with carbon monoxide as hereinafter described.

The organic compounds in which the cuprous salts may be formed and with which such salts are immediately complexed may include any of a rather large number of such compounds. Generally, however, the organic compounds are aromatic hydrocarbons. Such aromatic: hydrocarbons may contain a single aromatic ring or may contain two or more aromatic rings, either condensed or noncondensed. In addition, the aromatic hydrocarbons may have substituents to the ring or may be condensed with one or more other ring structures which are paraflinic or olefinic in nature. Nonlimiting examples of aromatic hydrocarbons suitable for use in preparing the cuprous salts of the present invention are benzene, toluene, the xylenes, various other polymethylbenzenes, such as mesitylene, isodurene, tri-, tetra-, pentaand hexamethylbenzenes, ethylbenzene and the various polyethylbenzenes,

isopropylbenzenes, propylbenzene and the various polyisopropyl and polypropylbenzenes, the various butyl and pentylbenzenes and the like, the substituted benzenes containing two or more dilferent substituents such as ethyltoluene, isopropyltoluene, and ethylxylenes; naphthalene, the various methylnaphthalenes, and polymethylnaphthalenes, ethylnaphthalene and the various polyethylnaphthalenes, the naphthalenes containing propyl, isopropyl, butyl, and pentyl substituents; the substituted naphthalenes containing two or more different substituents such as methylethylnaphthalene, methylpropylnaphthalenes, etc; the various indanes such as methylindanes, ethylindanes, isopropylindanes, etc; the dihydronaphthalenes such as methyl, ethyl, propyl, and butyl substituted dihydronaphthalenes; the tetrahydronaphthalenes and the like. In the preferred practice of the present invention, the aromatic hydrocarbons most often employed as the organic compound in forming the complexes of the present invention are benzene, naphthalene, partially hydrogenated naphthalenes and the various alkyl substituted derivatives of these wherein the alkyl substituents have no more than four carbon atoms per substituent. Within this group of preferred aromatic hydrocarbons are such compounds as benzene, ethylbenzene, toluene, the xylenes, naphthalene and the methylnaphthalenes, dihydronaphthalenes and the tetrahydronaphthalenes. A particularly useful group of aromatic hydrocarbons for use in forming the complexes is that including such compounds as toluene, ethylbenzene, ethyltoluene, the xylenes and tetrahydronaphthalene.

The method of preparing the cuprous fiuoroboratearomatic hydrocarbon containing complex which is used as a basis for forming the carbon monoxide containing complex employed in the process of the present invention for the separation of hydrocarbon mixtures may be any of those methods conventionally used. In US. Pat. 2,953,589, the preparation of cuprous fluoroboratearomatic hydrocarbon complexes by the introduction of powdered copper, BF and anhydrous H-F into benzene or other aromatic hydrocarbons is disclosed. This method may be used for the purposes of the present invention. In addition, the cuprous fiuoroborate-aromatic hydrocarbon complex may be prepared by dispersing OUF 2H O and metallic copper in an organic compound such as an aromatic hydrocarbon, and heating the reaction mix ture whole introducing gaseous BF into the dispersed medium. This method is described in Journal of the American Chemical Society, vol. 74, page 3702, 1952. This latter described method is preferred for the practice of the present invention. In addition to these two methods of preparing the cuprous fluoroborate-aromatic hydrocarbon complex, any other of the methods known to those skilled in the art may be used.

Preparation of the cuprous fiuorophosphate-aromatic hydrocarbon complex also may he by any of those means known to those skilled in the art. Preferably, however, this complex is prepared by introducing anhydrous CuF or CuF -2H O, metallic copper and phosphorous pentafluoride into an aromatic hydrocarbon medium and heating with agitation to an elevated temperature in excess of C. The cuprous fluorophosphate-aromatic hydrocarbon complexes may on occasion be solid at room temperature and therefore, must be maintained at elevated temperatures for use in the process of the present invention or, in the alternative, be used along with a suitable solvent. It is believed that impurities in the system cause these complexes to be solid. Among the solvents useful for maintaining the cuprous fiuorophosphates in liquid phase are those containing oxygen and/or sulfur. Such solvents include ethers, ketones, sulfones, disulfides, thioethers, thioureas, nitro alkyls and aryls, trihydrocarbonylphosphines and the like. While the particular solvent selected is primarily a matter of individual choice, it is somewhat preferred that the solvent be one selected from the group consisting of the alkyl and aryl sulfones, particularly such compounds as sulfolane and the alkyl sulfolanes.

The cuprous fiuoroborate and cuprous fluorophosphate complexes prepared as above described, are believed generally to contain one mole of cuprous fiuoroborate or cuprous fluorophosphate, as the case may be, and three moles of the aromatic hydrocarbon. For the purposes of describing the present invention, it may be assumed that these complexes are in this form. This first complex is then contacted with carbon monoxide in order to form the carbon monoxide containing complex which is employed for the separations process of the present invention. In this manner, either all or part of the aromatic hydrocarbon molecules in the first complex may be replaced with carbon monoxide. However, for practical considerations, it generally is preferred to displace only a portion of the aromatic hydrocarbons within the first complex with molecules of carbon monoxide. For example, the cuprous fluoroborate complex having all three moles of aromatic hydrocarbon replaced with carbon monoxide, is solid under normal conditions and therefore, is usually avoided in order to avoid the difficulty of the mechanical handling of solids. However, if desired, such solid complex may be dissolved in a suitable inert solvent and so utilized. The degree to which aromatic hydrocarbons are displaced by carbon monoxide in forming the carbon monoxide containing complex is largely controlled by temperature and carbon monoxide concentration during the contacting of the carbon monoxide with the initial aromatic hydrocarbon containing first complexes. At a given temperature, as the carbon monoxide partial pressure is increased, the number of moles of aromatic hydrocarbon in the first complex which will be replaced by carbon monoxide increases. For example, at 60 C. and a carbon monoxide partial pressure of approximately 35 p.s.i.a., the average number of carbon monoxide molecules introduced into a cuprous fluoroborate-toluene complex was approximately one, whereas at 100 p.s.i.a., the average number was approximately 2.35 moles. Conversely, as the concentration of carbon monoxide is held constant and the temperature is decreased, the number of moles of carbon monoxide introduced into the complex increases. For example, at a carbon monoxide partial pressure of 100 p.s.i.a. and a temperature of C., an average of one mole carbon monoxide is introduced, whereas at 70 C., approximately two moles are introduced while at approximately 30 C., three moles of carbon monoxide are introduced. Usually, carbon monoxide partial pressures Within the range of 15 to 200 p.s.i.a. are employed with temperatures within the range of 0 to C., the higher temperatures being utilized with the higher partial pressure and, conversely, lower temperatures being used with lower carbon monoxide partial pressure in such manner as to adjust the carbon monoxide complex to one containing an average of 1.0 to 2.75 moles carbon monoxide per atom of copper.

The amount of the carbon monoxide containing cuprous salt complex employed in carrying out the separations process of the present invention generally is such as to produce a mole ratio of such complex to the complexible hydrocarbons within the mixture to be separated within the range of 0.3 to 1.0. More preferred, however, are mole ratios within the range of 0.5 to 0.66. The complexible hydrocarbons within the mixture to be separated will be the aromatic hydrocarbons in the case of mixtures of aromatic and saturated aliphatic hydrocarbons, unsaturated aliphatic hydrocarbons in the case of mixtures of aromatic and unsaturated aliphatic hydrocarbons, and vinyl aromatic hydrocarbons and aromatic hydrocarbons. As mentioned above, the term vinyl aromatic hydrocarbons as used herein refers to those aromatic hydrocarbons having substituents thereto which contain ethylenic unsaturation. Along with this, the term aromatic hydrocarbon, as used herein, is not meant to include such vinyl aromatic hydrocarbons.

The temperature at which the hydrocarbon mixture to be separated is contacted with the carbon monoxide containing cuprous salt complex in most instances is Within the range of to 60 C., preferably to 50 C. The pressures at which the contact of the hydrocarbon mixture to be separated is made with the carbon monoxide containcuprous salt complex may vary considerably, ranging from subatmospheric to superatmospheric pressures of as high as 250 p.s.i.g. and higher. As a practical matter, it generally is preferred to carry out the separations process of the present invention at pressures at or near atmospheric, i.e., 0 to 10 p.s.i.g.

The aromatic hydrocarbons, unsaturated aliphatic hydrocarbons or vinyl aromatic hydrocarbons, depending upon the mixture being separated, which are selectively complexed by the carbon monoxide containing cuprous salt complex may be recovered by any means available. Elevated temperatures of 30 to 100 C. generally will suffice to remove the selectively complexed aromatic hydrocarbons from the resulting complex. Reduced pressures also may be employed to recover the selectively complexed hydrocarbons. A particularly useful means of recovering the aromatic hydrocarbons, unsaturated aliphatic hydrocarbons or vinyl aromatic hydrocarbons, as the case may be, involves displacement of these hydrocarbons with carbon monoxide. In this recovery means, the compleved hydrocarbons are displaced by contacting the complex of which they are a part with carbon monoxide. The temperature and/or partial pressure of the contacting preferably is adjusted such as to avoid complete displacement of the complexed hydrocarbons by carbon monoxide which would result in formation of a solid complex. Such temperatures preferably are within the range of 0 to 90 C. with carbon monoxide mole ratio to hydrocarbons in the complex of 1.0 to 2.75. In this manner, a portion of the complexed hydrocarbon may not be recovered, however, it is not lost and can be recovered at a later time by other means or by complete displacement with carbon monoxide. In this manner, not only are a portion of the complexed hydrocarbons displaced from the complex but the carbon monoxide containing cuprous salt complex is thereby regenerated. This displacement method of recovering the complexed hydrocarbons with carbon monoxide offers an additional advantage over and above merely regenerating the carbon monoxide containing cuprous salt complex, this advantage being that instead of pure carbon monoxide being contacted With the hydrocarbon containing first complex, a mixture of carbon monoxide and other difliculty separable gases such as hydrogen, nitrogen, methane, carbon dioxide, ethane, and the like may be utilized thereby effecting the separation and recovery of the carbon monoxide therefrom.

In practicing the separations process of the present invention, contact of the aromatic containing hydrocarbon mixture to be separated with the carbon monoxide containing cuprous salt complex results in the formation of two phases, an extract and a raffinate phase. The extract phase is comprised of the cuprous salt and the hydrocarbons selectively complexed from the mixture to be separated and those molecules of aromatic hydrocarbon which remain in the carbon monoxide containing cuprous salt complex after its formation. The reafiinate phase will contain primarily those hydrocarbons of the mixture to be separated which were not selectively complexed with the carbon monoxide containing cuprous salt complex. Substantially all of the carbon monoxide displaced by the hydrocarbons in the separations step passes immediately from the separations system and therefore, does not in any manner result in the formation of new mixtures which are themselves inconvenient to separate. This, of course, offers substantial advantage in that the requirements of downstream processing equipment for the separation and recovery of the desired materials from the extract and raflinate phases is substantially minimized.

The aromatic hydrocarbon containing mixtures which may be separated in accordance with the present invention generally fall into three groups. The first of these groups includes mixtures of aromatic hydrocarbons with saturated aliphatic hydrocarbons from which mixtures the aromatic hydrocarbons are preferentially complexed with the carbon monoxide containing cuprous salt complex. Another group of aromatic hydrocarbon containing mixtures separable by the process of the present invention are mixtures of aromatic hydrocarbons and unsaturated aliphatic hydrocarbons from which mixtures the unsaturated aliphatic hydrocarbons are selectively complexed by the carbon monoxide containing cuprous salt complexes prepared in accordance with the present invention. The third group of aromatic hydrocarbon containing mixtures separable by the process of the present invention are mixtures of aromatic hydrocarbons and vinyl aromatic hydrocarbons from which mixtures the vinyl aromatic hydrocarbons are selectively complexed. From the standpoint of operability, the hydrocarbon mixtures to be separated may vary quite widely in molecular weight range. However, as a practical matter, the present invention is most applicable to those hydrocarbon mixtures containing principally hydrocarbons of five to twenty carbon atoms per molecule. It is most useful in the separation of such mixtures containing six to ten carbon atoms per molecule. Within this range of hydrocarbons are such aromatic hydrocarbons as benzene, toluene, ethylbenzene, the xylenes, polyethylbenzenes, naphthalene, methylnaphthalene dimethylnaphthalenes, ethylnaphthalenes, methyethylnaphthalenes, and the like. Among the vinyl aromatic hydrocarbons which may be separated and recovered are such materials as styrene, alpha-methylstyrene, betamethylstyrene, vinyltoluene, divinylbenzene, vinylnaphthalene, divinylnaphthalene, vinylmethylnaphthalene, and the like. Included within the monaromatic hydrocarbons which may be separated are both saturated and unsaturated aliphatic hydrocarbons. Such unsaturated hydrocarbons as the olefin and diolefin hydrocarbons, both acyclic and alicyclic may be separated from aromatic hydrocarbons in accordance with the process of the present invention. Also, such saturated hydrocarbons as parafilns and naphthenes may be separated from aromatic hydrocarbons. Included Within this group of unsaturated and saturated hydrocarbons are such compounds as the hexenes, hexadienes, heptenes, heptadienes, cyclohexenes, cyclohexadienes, methylcyclohexenes, n-hexane, heptane, cyclohexane, methylcyclohexane, cycloheptane, dimethylcyclohexane, vinylcyclohexane, vinylcyclohexene, noctane, octenes, cyclooctadiene, octadienes, n-decane, poly methyl heptanes, methyl nonane, methyl nonanes, cyclopentadiene, dicyclopentadiene, and the like.

To further describe and to specifically illustrate the process of the present invention, the following examples are presented. These examples are not, however, to be construed as limiting of the present process.

EXAMPLE I A carbon monoxide containing complex of cuprous tetrafluoroborate was prepared as follows: a complex of cuprous fluoroborate and toluene was prepared by passing an excess of BF gas into a vigorously agitated mixture of 138 grams of cupric fluoride dihydrate (CuF -2H O) and 70 grams of finely divided, hydrogen-reduced metallic copper dispersed in toluene maintained at its boiling point. Water of hydration was continuously removed by means of a separator connected to a reflux condenser. After an essentially homogeneous solution had been obtained, excess solubilized BF was removed by refluxing. On cooling, excess toluene phased out of solution as an upper layer and was separated from the complex.

Seventy-one (71) grams of the complex above prepared; which contained 25.0 grams of CuBR; (0.166 mole) and 46 grams toluene (0.5 mole), were treated with carbon monoxide gas by sparging the gas into the solution at ambient temperature and atmospheric pressure. An upper layer of 30 grams of toluene (0.33 mole) phased out of the complex and was separated. The complex absorbed 9.0 grams of carbon monoxide in the process.

To approximately 50 grams of the cuprous fluoroborate-carbon monoxide-toluene complex so prepared was added 70 grams of a mixture of hydrocarbons having the following composition:

Component: Weight percent Benzene 38.9 Toluene 30.9 'Ethylb enzene 8. 1 P- and m-xylene 9.0 O-xylene 3.5 C aromatics 2.7 Nonaromatics 6.9

The aromatic content of the resulting mixture of hydrocarbons and complex represented approximately 0.7 mole. The separations mass was warmed to 75 C. whereupon vigorous evolution of ca bon monoxide gas occurred. A final temperature of 90 C. was employed to insure disassociation of the carbon monoxide complex and replacement by the aromatics. A supernatant layer of unreacted hydrocarbon formed after cooling to approximately 25 C. This layer was separated and carbon monoxide gas then bubbled into the cuprous tetrafiuoroborate-aromatic complex extract phase at ambient temperatures (2526 C.) to produce 11 grams (0.12 mole) of an aromatic concentrate raifinate released by the cuprous salt reacting with carbon monoxide. This recovered hydrocarbon concentrate had the following composition:

Components: Weight percent Benzene 32.5 Toluene 47.4 Ethylbenzene 6. 1 P- and m-xylene 7.4 O-xylene 2.6 C aromatics a- 2.5 Nonaromatics 1.5

The nonaromatic hydrocarbons were reduced from 6.9 percent to 1.5 percent in a single stage in an aromatic concentration region where conventional liquid-liquid extraction is relatively inefiicient. Along with this, the loading of the complex by the contained aromatics ultimately exchanged was 44 weight percent which is greater than that obtainable with most conventional liquid-liquid extraction agents.

EXAMPLE II A cuprous tetrafiuoroborate-toluene complex was prepared as described in Example I, and 71 grams thereof Component: Weight percent Benzene 44.1 Toluene 26.5 Ethylbenzene 7.0 P- and m-xylene 7.9 O-xylene 3.0 C aromatics 2.7 Nonaromatics 8.8

The complex was heated as described above in Example I whereupon carbon monoxide was displaced and removed from the system. Unreacted hydrocarbon formed and upper rafiinate phase and was separated, analyzed and found to contain 11.0 weight percent nonaromatics (paraffins and na-phthenes). The complex or extract phase "was found to contain 17.0 grams (0.18 mole) of hydrocarbons replaceable by carbon monoxide, the hydrocarbons having the following distribution:

Components: Weight percent Benzene 33.6 Toluene 40.2 Ethylbenzene 6.0 P and m-xylene 10.1 O-xylene 5.0 C aromatics 3.9 Nonaromatics 1.2

The aromatic content of the feed to the carbon monoxide complex was enriched from 91.2% aromatics to 98.8%- aromatics content in a single stage with a concurrent reduction of nonaromatic hydrocarbons of 86.4%.

What is claimed is:

1. A process for the separation of mixtures of hydrocarbons containing aromatic hydrocarbons, said process comprising contacting such aromatic hydrocarbon containing mixture with a complex containing carbon monoxide in complex relationship with a cuprous salt selected from the group consisting of cuprous fluoroborate and cuprous fiuorophosphate, said carbon monoxide having displaced an aromatic hydrocarbon to form said complex, whereby at least a portion of said carbon monoxide is expelled from said complex and replaced by a portion of the hydrocarbons in said mixture, thereby forming an extract phase and a rafiinate phase, separating said extract and raifinate phases and recovering from said extract phase those hydrocarbons of said aromatic hydrocarbon containing mixture contained therein.

2. The process of claim I wherein said aromatic hydrocarbon containing mixture is one containing aromatic hydrocarbons in admixture with saturated aliphatic hydrocarbons.

3. The process of claim 1 wherein said aromatic hydrocarbon containing mixture is one containing aromatic hydrocarbons in admixture with unsaturated aliphatic hydrocarbons.

4. The process of claim 1 wherein said aromatic hydrocarbon containing mixture is one containing aromatic hydrocarbons in admixture with vinyl aromatic hydrocarbons.

5. The process of claim 1 wherein said cuprous salt is cuprous fluoroborate.

6. The process of claim 5 wherein said complex comprises cuprous fluoroborate, aromatic hydrocarbons and carbon monoxide in a molecular ratio of 1:1:2.

7. The process of claim 6 wherein said complex is prepared by forming a first complex of the cuprous salt and an aromatic hydrocarbon and thereafter contacting said first complex with carbon monoxide at a temperature Within the range of 10 to 100 C. and a carbon monoxide partial pressure within the range of 15 to 200 p.s.i.a.

8. The process of claim 7 wherein the aromatic hydrocarbon is one selected from the group consisting of benzene, naphthalene, partially hydrogenated naphthalenes and alkyl substituted derivatives of these wherein the alkyl substituents have no more than four carbon atoms per substituent.

9. The process of claim 1 wherein the hydrocarbons are recovered from the extract phase by contacting said extract phase with carbon monoxide at a temperature within the range of O to 90 C. and a carbon monoxide partial pressure of 15 to 200 p.s.i.a.

References Cited UNITED STATES PATENTS 2,830,105 4/1958 Mackor 260674 2,953,589 9/1960 McCaulay 260674 3,206,521 9/1965 Long 260-674 HERBERT LEVINE, Primary Examiner US. Cl. X.R.

(5/69) UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 578, 581 Dated May 11, 1971 Inventofls) George D. Davis et 211 It is certified that error appears in the aboveand that said Letters Patent are hereby corrected as identified patent shown below:

Column 1, line 6, the name "George F. Davis" should read "George D. Davis".

Signed and sealed this ZL th day of August 1971.

(SEAL) Attest:

EDWARD M.F'LE'I'CHER,JR. WILLIAM E. SCHUYLER, JR. Attesting Officer Commissioner of Patents 

